I have take over a old devices for testing but I can’t add hen my cloud,
I get a error device/license already taken and I also not factory reset the device
Use the support center link to create a new case. When asked for case type, choose customer care.
Include to serial number of the device, and a picture of the serial number barcode as an attachment in the case.
The licensing team can have the device moved to your account. This is a manual process as we need to review each one to confirm you have access to/own the device.
WatchGuard Customer Support